From its name, it may be difficult to understand what bipolar disorder is. Another name of this disorder-manic depression may give a clue. As this name suggests, there will be manic and depressive symptoms in someone with manic depression. Depression may be more familiar to most of us. What is mania? When a person becomes manic, he will be extremely elated and his mood state will be the exact opposite of someone who is depressed. When someone has bipolar disorder, his mood will swing between depressive and manic phase. This usually lasts several weeks or months and is far beyond what most of us experience. Sometimes, the patient will have a mixed state, e.g. he may have depressed mood with restlessness and overactivity of a manic episode.

You can refer to the following website.

What is bipolar affective disorder?

The source of information is provided by the Hospital Authority Castle Peak Hospital